Patrick O'Neal, age 10, of Diamond, West Virginia, for his question:
Do the astronauts see the stars?
Naturally the most suitable person to ask would be an astronaut, so one of Andy's devoted helpers asked Astronaut A1 Worden, who piloted the command module during the Apollo XV mission to the moon. The answer was a very definite Yes. When an astronaut looks out through the module porthole, he does indeed see the stars. In fact, he sees such a stupendous sight that our view of the starry heavens from down here seems hardly worth mentioning.
While Astronaut A1 Worden orbited around the moon, he had a chance to see the stars above the daytime side of the moon and also on the opposite, dark side. At all times, the background of the lunar sky was stark black, blacker than the blackest midnight. There were stars, brilliant unblinking stars even in parts of the daytime sky but more, many, many more in the skies of the lunar night.
We look up at the sky through hundreds of miles of airy atmosphere and our view is screened by teeming gaseous molecules. During the day, they scatter the short waves of sunlight to color our sky with heavenly blue. After sunset, the airy gases manage to hide most of the stars that shine down on our earth. Even on the clearest night, when the whole sky seems crowded with sparklers, we could count only about 2,000 stars.
The brightness of the visible stars is measured in degrees of magnitude. A star of first magnitude is two and about half times brighter than one of second magnitude. A second magnitude star is two and a half times brighter than a third magnitude star, and so on. On this scale, first magnitude is about one hundred times brighter than sixth magnitude. And a star of sixth magnitude is the dimmest dim star that our human eyes can see from the earth.
The astronauts leave the earth's atmosphere behind them and see the heavens without its veil of airy gases. From their portholes, the most brilliant stars, they see from the earth become one hundred times brighter. The dimmest stars we see from the earth become brighter than those we see as first magnitude stars. Naturally, this means that hosts of dim and still dimmer stars become visible as big bright beauties.
Though we barely see sixth magnitude stars, our telescopes reveal that the heavens are crowded with stars of eighth, ninth and even dimmer magnitudes. Astronaut A1 Worden reports that while orbiting the moon, it was possible to see stars of ninth and even tenth magnitudes. Imagine how many, many more teeming stars must be visible from out there in the airless lunar skies!
However, even there the dazzling sun tends to steal the stage. During the lunar day, fewer stars are visible in the neighborhood of the sun. But there are plenty of be seen when a person turns away from the sun to look at some other part of the sky. And at night, when the sky is screened from the sun and shrouded in the moon's shadow the black, black sky is populated with teeming hosts of brilliant stars. The astronauts behold a sight far more stupendous that we can imagine.